bdone: You still may want to use bashcompinit since that is the way to have Zsh follow the complete bash spec. While Zsh is picking up the source file, it may not always work depending on implementation in the completion file.

Not sure on that Dieter. I can type drush and then a few characters, followed by tab and I get options. The only thing I notice is that I have to ctrl-c to start over. Backspacing doesn't reset the autocomplete.